What's the best thing to do with "extra" domain names?

Using one of them and the other two are similar...

[HughMungus]

I have three domain names. One I'm actually using as the name of a business and as the website for the business. Because I couldn't initially decide which of the three domain names to use, I have two other, similar domain names (different words, same concept).

From a google and search engine and general visibility point of view, what's the best thing to do with the other two domain names? Redirects to the main site? Similar but different content with links to the main site? Or is this a worthwhile pursuit at all?

TIA!

[WebGuerrilla]

If you are going to use the additional names for type-in or offline marketing, you should set them up either as duplicate sites with a robots.txt that excludes bots, or a 301 redirect to the main site.

Either way, humans using the other domains will get to your site, but bots won't end up indexing the same content under different domains.

[Tropical Island]

>Similar but different content with links to the main site? <

If you have the time and the resources then this would be the best solution.

Over time as you pick up back-links all sites will benefit.

If you use the other two sites to highlght mispellings, secondary products, etc. you can only end up benifitting. Just be careful not to overdo it and there should be no problem, with the search engines. By this I mean different content. If there are a number of divisions or product lines aim each site at one with refferals back to the other sites for the other products.

[2_much]

The only problem with setting them up separately is that you split the link pop. The advantage of having one main domain that you prmote is that you can focus entirely on getting links for that one name. On the other hand, if you set the other ones up with unique content, you can link them with each other, but you still need to get inbound links for all three so that it's not a closed loop.
Given this, what I would do would be to set the three domains up, and redirect the other two using a 301 like WG said to the main site. Or, if you don't think you'll use those, just let them go.

[ogletree]

Well sometimes it helps to have different sties that are more informational that would draw backlinks that you culd not get for your main site. That way you would not be splitting them up.

[nutsandbolts]

redirect 301 / [wibblewobblewidgets.com...]

I always use this in a .htaccess file to re-direct via 301