TFL means Too (something) Long.....
In other words, someone has sent a text that is very wordy, and you just don't feel like
reading it.
If I were to ramble on in this explanation like it was Robert Louis Stevensons 'Treasure Island'
(great book by the way), then you would read the first part,
and not read the rest, but answer back, TFL
Those More-Roons that respond back with Tip For Life, and something about Transport
have done nothing more than a quick Google.
This answer is a great example of TFL.