I'm getting attacks from Geni's servers as well. Apparently they have been infected with some sort of malware.
Until they resolve the issue, make sure your antivirus software is up-to-date, and whatever you do, do NOT follow any prompts to download software that will supposedly "fix" the problem. (This is what malware programs like to tell you, when the truth is they're trying to get you to infect yourself.)
Geoffrey David Trowbridge can you tell me which page is prompting you to download software?
@Michael: The page doesn't seem to matter, but FWIW, it always seems to occur within 15 to 30 seconds after logging in. The user's browser window gets hijacked and redirected to the host site for the malware. Once there, the user is in an endless loop that can only be ended by closing the browser.
Note that the Google Chrome browser will no longer allow any user to access Geni.com without first acknowledging that the site is known to host malware and could be dangerous.
Those warnings are not from ANY security software. Those warnings are coming from existing Malware already on your system.
In the last 48hrs there has been a new email worm making the rounds. As an IT admin we had one of our employees hit by it.
Take a look at that screen shot, if you don't work IT you would never know that what you are seeing is Malware trying to convince you to click on it and install more Malware. I've seen this time and time again where it looks so real, but it's not.
As to why it's only attacking Geni ? Something unique about Geni is triggering it into action. Could be the login, could be https access, could be a keyword on one of the Geni webpages.
If what you are seeing looks anything like that screen shot you need to have your machine looked at by a professional. I've cleaned dozens of infections like this one. I'm sure I'll see more in the future.