I just realized—it's probably a great investment to buy common misspellings of your own company's name. They can bring more traffic to your site (and keep you from having to pay name sharks.) If your company decides they don't need them, you can probably flip them for a big profit.
Your company's got to be pretty huge before they're worth anything significant, at which point the cash isn't worth the hassle of having someone leeching from you.
Yes, I try to get every 1-2 step removed likely variation (if it is two words, get the concatenated and dash variants, get the various gTLDs (at least .com/.net), easy misspellings, etc.
An annoying thing for me is that right now for my company I have ~everything except first-last.com, which is taken by another company in the general field (but unused). firstlast.com is the primary form, but since it is two words, the dash variant is pretty important.
Probably not that great of an investment. If you can get it for cheap, why not. Most users I've encountered don't even use the domain name anymore. They "Google it" and click the link that Google brings up.
If anything your probably better off buying adwords for your company.
Indeed. Twiddla still gets a dozen hits a day from people typing "twidla.com" into their browser. I'm sure we have users who think that's the correct name.