I rarely talk because I'm most spamming content. But, 7/8 of my linkshells are usually active, with my 7th, "SuperNicePeople" being the most active. In no particular order:

Linkshell 1: GFAQS-Mlbro.1 year!!
Was a day one linkshell created from a user on GameFaqs.

Linkshell 2: The Aetherial Guard
This was my first serious linkshell. Many day one players are still in this one. It's been mildly quiet lately, though, but always a lot of prople online.

Linkshell 3: Static coil groups
As it says. Unfortunately, many folks here are in completely different linkshells and FCs for their raids. Due to my work schedule, it's kinda odd that I STILL can get a group to match my timing.

Linkshell 4: T6-9 n Primals
Same as the above. I help on Primals when I'm on, though.

Linkshell 5: Hunt LS 2.0
My third-favorite linkshell for obvious reasons.

Linkshell 6: Skinky Bastards
A combination of serious players and humorous players.

Linkshell 7: SuperNicePeople
Extremely, extremely, extremely active linkshell. Many players here work hard to help people with stuff, even if they group up and take one person in at a time to ensure everyone get their win. Many of us veterans, many new, many who just want company. They are humorous, but when it's time to battle, they are serious. My favorite linkshell.

Linkshell 8: Light Farmers
A linkshell used for farming lights for Zodiac weapon quest line. Not many members, though. I'm shy'ing away from the grind, so I only join them when I am off work to ensure I make the most of the grind.