The plan is to slowly cover more and more TLD-s. Each TLD's whois has it's own formatting of data so we need to make parsers for each case. Well at some point they will start repeating. I am aware that adding more tld-s in necessary, now even more aware. :)

With allowing all TLD's comes the problem. Do you have to also show all search engines? It's a problem of usability and scope.

For example, being from Russia, I have hard time immediately using the service because most sites that I might input to the application end with .ru. But if the app allows .ru TLD, to be useful to me it should also show me Yandex and Rambler indexing stats, and then Google and Yahoo too. But not the Indian or Australian ones, please, or I'll be overwhelmed with the information. See, there's the problem.

Yes, this is a very good observation. If you have a local website, then you want to have local related information about it. For example I wanted to create a localized version for my country (Slovenia), with adding a local search engine and google.si stats to search engine stats, and local directories. But this is hard to scale and as you note the scope becomes a big problem.

If we will go covering local search engines at some point the scope problem could be solved by offering you to choose from list of (ever growing) supported resources which you want to see in addition to general google/yahoo/alexa.

Also, I find it inconvenient to switch between edit mode and non edit-mode.

When the user log in for the first time, it would be nice to have a wizard to easily add one site. it doesn't make sense to have to click on "Enable edit" because I cannot do any other action at this stage.

I didn't want edit controls to pollute the interface because after you initially enter your domains your edit vs viewing slice of time will be very minor.

Yes, this is very valid point. I will think about how to make it work as you describe. Thanks!