Here's what I'd do. + - Karma was tried on this site a while back and demised due to abuse.. Simple likes are great for social fora and non specific chat.
If we take a subject such as dodgy bolts, or party in Bagshawe, IMO the point of those is to share info, if you feel strongly about it, type a response saying so - all is marginal so a few posts every now and then are a good thing from the site's perspective. Any likes their should be for Pete and co. who cleaned it up, not for the topic of (to extrapolate) party in Bagshawe Cavern....
Club fora - let them do what they want, their material will go into the canon and if SUSS for example want to have a social media type platform, why not. Again though, if a club had a post on 'got pissed, destroyed cave' then likes would be bad news.
Tackle, trips, etc. - IMO 'likes' etc. are not useful per se - e.g. if someone says 'my Speleotechnics light was dodgy' and 300 people agree and thus 'like' it, that wont help anyone. If someone posts a way of fixing said light and gets 100 likes, maybe 100 people fixed their light, 200 bought another (lets say a Duo) and it was bombproof and got 200 likes, which post is best? etc. etc.
This forum has been relatively 'quiet' for as long as I remember (i.e. from its inception) and I compare it with ukbouldering which took flight at the same time, and I guess there are a: fewer cavers than boulderers and b: cavers are less inclined to talk about the extraneous stuff (all this excepting the general ukcaving forum where we've seen allsorts). All this is to the good as I see it. It isn't a facebook analogue and nor should it be. It's become a place for solid information based on folk going underground and doing it, and if it stays slow as a result I'd prefer it that way. I also understand that cavers are people who also want to chat, make friends, cut loose and talk bollocks to each other, so likes and dislikes would be nice - but as I've seen on another forum I frequent where it's almost the norm to be an utter c*nt unless it's in the serious bit, it's just a free-for-all...
So, I'd either consider it carefully on the 'proper' fora (i.e let those results appear organically due to useful content which they do already), just do it all over and f**k it and let the users self-police it(hence let likes appear on BS threads) or not bother - or just keep it to the chat.
Alternatively create a facebook group for the chat.... if SMF can link into it it could be perfect...
However harking back to mmilner's strop... don't waste 3 hours and do nothing, and stick up 2 fingers to the countless 'professional cavers' who avoid the site.....
Can I use a
now?