Today I have discovered that Gmail (Google's E-mail service, to those living under a rock) had decided to increase their user base by allowing secondary (referred by existing members) to invite up to 3 of their friends to Gmail. The popularity of the service still seems high despite the privacy issues some people choose to be panicky about as my 3 invites were gone in a matter of minutes. Although Google was clearly not ready for the influx of the new users, since all of the people whom I sent the invites reported seeing an error message saying that the service is temporarily unavailable. This was further confirmed by few other people who got invites from other people. This however is not really the the most interesting thing. What is quite interesting is that 2 premier free e-mail (and pay?) providers, Yahoo and Hotmail (MS) have blocked Gmail invites. At first I was a little sceptical of this, despite the long thread on this topic on Slashdot, however when I sent one of my friends a Gmail invite to a Hotmai...