The truth is, Adam that there is no such thing as a homogenous community of older people using the internet and needing to all be addressed by the same term.
There are people who :-
Have been using it since the Beeb put out the first BBC Micro,
Bought the first Apple computers when Apple was a with-it name with Beatle connections,
Have just taken the plunge and found out what the heck they are supposed to do with it,
Just want to shop at amazon,
Buy everything online,
Look for new recipes and knitting patterns only,
Can't cook or knit,
Google all new words and concepts,
Have been designing websites since you were in babygros,
Don't know what URL stands for,
Like to be called Silver surfers,
Can't stand being called silver surfers,
Frequent dating sites,
would never visit a dating site,
Frequent sites with pics of hunky blokes in the nude,
Would have a fit if they saw an online pic of a willy,
Don't like all being lumped together as though they are identical.
How do you address those who are not "seniors"? Is there one term for everyone? If it covers everyone, surely it covers those who are a little older as well as those who are a little younger?