Disclaimer: Thar be affiliate links here. I have to support this blog somehow, so some of the links in here will earn me a buck or two, should you choose to sign up for the relevant service. But that in no way affected my review. K?

At a recent event, someone asked me what the best keyword research tool is.
I said “Your brain”.
But that got me thinking – there are lots of cool tools out there. How do they really stack up? I took a very subjective look at 8 of them. Here’s what I found:

Google Adwords Keyword Research Tool: Free

Google’s keyword research tool is free, and requires no registration. And, of course, they’re pulling data from the busiest search engine on the web.
Features include:

• Easy, intuitive keyword entry and research.
• Keyword search volume per month.
• Trending data.
• PPC bid data, if you’re doing pay per click marketing.
• Ability to download a CSV file, if desired.

It’s not a bad place to start. But it has some limitations:
It’s meant to make you buy PPC ads. I find the data a little suspect when researching organic SEO terms.
Some keyword suggestions may make you scratch your head. I tested ‘conversation marketing’ and Google suggested, among other things, ‘conversations with women’. Hmmm.
The verdict: The Google keywords tool is fast, free and built on an immense database. You’d be stupid not to use it, but supplement with data from another source.

WordTracker: $59/month

I’ve always loved WordTracker. You can build a keyword list, compare them across search engines, and get competitive data all in one place.
I won’t bother loading my page down with screen captures – you can see a tour here.
Features include:

• Ability to grab keyword data from multiple search engines, including Google.
• Export to CSV and other formats.
• Misspelling search.
• An API, if you’re wealthy and/or a glutton for punishment.

Wordtracker is definitely pro-grade. I do have a few concerns, though:
Their KEI formula seems a bit wonky, and doesn’t always match up with our findings regarding keyword traffic, quality and competition. I did them a disservice here – Wordtracker has updated their KEI algorithm and it’s looking a lot better now. I won’t go into the math – it’s Saturday.
Read my even better review of Wordtracker, where I discuss a number of massively cool new features here.
And, of course, it costs $59/month. It’s an absolute bargain.
The verdict: Use this with Google’s free tool and you’ve got a solid combination. If you’re a pro, you have to have this or Keyword Discovery (see below). If you really want great data, get ‘em both.

Wordstream’s Free Keyword Tool

Wordstream’s free keyword tool is more limited than Google’s. Their goal is different, too: They want you to sign up for their pay service.
Unfortunately, that difference means Google’s offering leaves them in the dust. Wordstream Free does a decent job of showing you possible synonyms and phrases, but offers no hard data regarding search volumes or trends. And they require that you enter your e-mail if you want to save the keyword list.
The verdict: Their pay tools are among the best in the industry. The free tool, though, does them a serious disservice. Wordstream, I suggest you do more to encourage free trials, and skip the freebies.

SEOPivot: You get what you pay for

SEOPivot is the most expensive of the tools I reviewed. It’s also the best opportunity gap analyzer you’ll find.
SEOPivot examines your web site, shows you keywords and ranking pages for those keywords, and shows the opportunity gap (‘potential’) for each keyword. You get to see your best potential keywords and your current placement for those keywords, all in one place.
Features include:

• Export in multiple formats (pay versions only).
• Report showing current ranking and ranking page.
• Query manager, so you can find previous research.
• API access (for a fee).

There is one potential drawback, though: SEOPivot builds your keyword list based on your site’s content and traffic, not a keyword list. It’s not a keyword research tool in the traditional sense. You can find missed opportunities, but you won’t find totally unknown sources of traffic.
Oh, and it costs $140/month if you want to export reports.
The verdict: SEOPivot is the best way to analyze keyword potential for both your site and your competitors’ sites. The only problem: Wordze (see the next tool) offers 70% of the feature set at a far lower price, and a keyword research tool. Be sure you’ve got WordTracker or something similar to triangulate results.

Wordze: A Swiss Army Knife

Wordze has by far the broadest toolset under one virtual roof. Features include:

• API access with basic membership.
• Competitive research similar to SEOPivot.
• Site analyzer for keyword richness.
• Keyword manager.
• Keyword research toolset.

I admit, I’m biased – I’ve written about Wordze before. But there’s a reason: They offer the broadest toolset I’ve seen, and they do it at a very reasonable price: $39/month.
You can also try some Wordze features for free. There’s a daily limit on queries, though, so don’t expect to really give the system a workout.
The verdict: No matter how you look at it, there’s no real downside to using this tool. Bloggers, search marketing beginners and pros looking to supplement existing tools must buy Wordze. It doesn’t bring anything new to the table, but it does put all the traditional fare in one place, and it’s a breeze to use. Order it.

Keyword Competitor: Did I miss something?

Keyword Competitor is puzzling to me. It’s got the most polished interface; it offers some brilliant competitive research tools similar to, or even superior to, SEOPivot. And it lets you monitor competitors.
But I can’t help feeling like this is a re-digestion of the Wordze and WordTracker toolsets.
It does offer competitor monitoring, which is unique among the tools I reviewed. But that’s not enough to justify the $95/month expense.
The verdict: If you don’t yet have a competitive keyword research tool, have a look at Keyword Competitor. Be sure to compare it to others, though, and let me know if you figure out the compelling difference between this and Wordze.

Keyword Discovery: Keyword geek paradise

If you’re a compulsive researcher, Keyword Discovery is the choice. Their database is humungous, export options abound, and you can slice and dice your data from more directions than a blender on ‘mince’.
Features include:

• Standard keyword research stuff: Searches, competition and the like.
• Misspelling finder.
• Ability to restrict data to Google, Yahoo!, etc..
• Ability to restrict data by industry, region or question phrases (my favorite, as you can see here.

At $70/month I’ve not regretted the fee, and I’ve used Keyword Discovery for a couple of years.
The only minus? They offer some tantalizingly cool additional features, but you have to pay for an upgraded membership of at least $199.95/month to get access to them. Sigh.
The verdict: If you want to out-geek everyone in the room, this is the tool for you. Order it.

Recommendations

If you’re looking to assemble a keyword research toolset, here’s what I suggest:
For pros: Sign up for Keyword Discovery and SEO Pivot. Use Google’s keyword tool to double-check data. Add WordTracker if you want the best kung fu around.
For bloggers: Wordze has everything you need. Add in Google’s keyword tool and you’re set. Add in Keyword Discovery or Wordtracker later on, when you’re feeling plucky.

Related reading

• Picking great keywords starts with great questions
• How to: Find great keywords and track ‘em
• The unscary, real-world guide to SEO copywriting