Unfortunately, yes it is; however, they do have promotions such as "SocialSunday", and there are users who has the ability to send invitations to new users. Although Socialscope may be perceived as the best Twitter client by some, it is limited to only 2 accounts AFAIK. Ubersocial and Blaq are alternative Twitter clients that work well & have the capability to add more than just 2 accounts. I personally have 3 accounts on each of these. I have not tried to add more than that though.
Well, IMO for a stand alone Twitter client only, I think the best is Ubsersocial. It can't be beat, hands down. Blaq is nice as it has other features such as being able to tweet even when it is not open or running in the backround, but I believe it still needs some more work (I also know that it is being upgraded currently in the dark). Also please note that When I speak of these 2 applications, I am speaking of the paid versions only, and have no idea or experience how the free versions would even compare.
Now, when you get into other things such as FaceBook, FourSqare etc, nothing can beat Socialscope, as it has all of these things integrated within and the functionality is great. So if you're looking for something that is well rounded for different social applications, Socialscope is where it is at. **On a side note, I do believe that Socialscope will continue to be developed to the point where the company will probably sell it off, and it will eventually come out of beta, and probably cost an arm and a leg to have. But this is only my opinion.**
As of right now, the closest thing to Socialscope as far as functionality is VodafoneUpdate which includes things like Twitter, FaceBook, LinkedIn etc. I think this is great as well when you're speaking of being able to access multiple platforms. It is free as well.
