I like them. No really, I do. They're great for passive outreach and sharing. They're awesome for research - you just follow the tag to riff on a topic. I am, however, starting to feel #spammed by the way some people are using them.
#rug #persianrugs #tiestheroomtogether
It's fair to say that uptake is slow amongst the average users, especially on personal accounts where security settings seem to make this all somewhat moot, but a lot of Facebook Page admins have charged into this with a degree of relish worthy of Heinz. So much so, many posts look ridiculous and there's a real chance of them alienating their community. I thought I'd throw my tuppence-worth in, for the record.
Don't use Them for Every Word
Stop it. Just, stop it. I've seen posts where almost every word had a hashtag in front of it, making the whole sentence just tags. It looks bloody stupid and your audience know they are being marketed to and that you no longer give a shit what your actually saying, just so long as someone sees it. It's not funny, or ironic, it's just bad practice. Bad Page admin, go to your box.
Keep Them Simple
It's not a game. You want to capitalize on others using your hashtag, so keep it as simple as possible.
Say your a crafts author like the good lady wife - tags like #jewellery (you might even want to try #jewelry), #steampunk, #crafts (maybe), or something like #beading or #cooking are going to be tags other people are going to use as well - and so the outreach on them (and chance of them being seen by genuinely interested parties) is going to be better. This isn't Twitter, so hashtags shouldn't have more than 2 words in them. Something like #steampunk is great, and #steampunkcooking might have it's place (if others are also using it), but #steampunkcookingonanengineblock is very likely a hanging offence.
#beer #carlsburg #couplesdatinginalex
There's one possible exception to this. Getting everyone to remember one tag (like #ourevent2013, or whatever) is sometimes easier. I you're trying to get people to submit photographs from an event, for example, using one tag across Google Plus, Twitter, Instagram, and now on Facebook, will always be the right way to go.
Cap at 3 or 4 of Value
Once again, don't spam your audience. Personally I've found 3 hashtags just about right, especially if you're still object tagging, location tagging, and all the other tactics. There's nothing written in stone here, but if you do any more it starts looking really obvious. If necessary add them at the end of what you're saying, though personally I don't mind them being part of the sentence so long as it looks natural. Also, bear in mind that hashtags don't act as links through the mobile interface so this can get shoddy pretty quickly on smartphones if it's tagged to bits but not linking anywhere - I'm reliably told this will, however, be coming on line in the next few days.
Find What's Appropriate
Take a look at what's popular by taking a look at a hashtag you think might work, and see what others are using as well (around the same subject). Right now topics and communities are still finding out what works and experimenting. You can poke around a stream and get to the content of a topic by using the URL structure like https://www.facebook.com/hashtag/bacon, where #bacon is the hashtag for the stream you want to look at. If you search on a hashtag through search (just type in #wordofyourchoice) you now also get a list of similar tags that other people are using, which I presume they'll be rolling out more functionality on soon. Do a bit of research to get the most bang-for-your-buck, and for gods sake think about it properly and what it's look like on the Page (no one wants another #susanalbumparty).
Don't be Flighty
If you have a core topic, try and stick with one core tag (the most appropriate that fits what you do) based on that topic. Play with the others, great, but tags are generating 'communities' around topics, and other admins (I've found) are sharing my tagged content more when I mention core topics (because they are using these tags to source topical content for their pages). If you're a digital artist and have a Page about your work, be sure to always use #digitalart (or whatever your peers are using) no matter what else you're doing. Rocket science it ain't. I fully anticipate different communities developing their own crowdsourced hashtags of choice as people become more confident with their use.
#harmless #campwaconda #ohmygodwereallgonnadie
So there you go. Facebook hashtags are still in their infancy, and we don't know where Facebook is going to go with this - or how they'll cleverly monetize it. It would be great if we could set some standards and best practices that are good for our communities and outreach instead of just using these for spam. When, after all, does spam ever work?