I think a lot of people might see this and think that it's not a big issue because they're not currently in this situation.
For those people, I'd like you to think of your first social Linkshell that really made you feel at home. Great experience, right. Of course it was. Now, can you imagine how terrible it would be to log on one day and want to talk to all of these new friends you made only to be denied access to the Linkshell due to having too many people online? I know I would never want that.
Ideas like splitting the shell and creating a second one wouldn't be a great idea in my opinion. Everyone would want to be in the main one, but they'd have to settle for second best in that scenario. A less than ideal situation, no?
Because of this, I think the best solution going forward is to increase the number of online Linkshell members allowed. Nobody has to settle for second best. New players get the full welcome. When someone is trying to talk to a few Linkshell members, they won't have to figure out which shells that the other people are in.