It appears they've even expanded, or will, with a new site- (sfrpg.starfrontiers.com). It is unclear what the purpose for it will be at this point. The original website is real nice and as a Top Secret/S.I. fan, I'm envious.
While Top Secret/S.I. has also enjoyed pretty healthy online support, it has never been granted permission to host the game material online for free. A few of us TS/SI fans have tried (Modus Operandi tried annually) with no success. That hasn't stopped some people. Spies.R.Us.org has had the rules online for several years. While there hasn't seemed to be a problem with this, I do not believe there has ever been permission granted to do so.
Now, the people who are behind the Star Frontiers site have been working on one for Top Secret/S.I. It has been promoted on the Frontiers site as 'coming soon' and has been for about two years. It is unknown if permission has been granted or if this is another site similar to the Spies.R.Us, that will have to be determined- if it is ever completed. There is the option of registering for the site and I did get an email from the administrator, but beyond that there hasn't been a lot of action.
Check out what is up so far. Top Secret/S.I.