> "you need it to promote your OSS stuff"
I have found this to be the biggest myth of Twitter: it is nearly useless for content marketing.
A long time ago (so it's possible this isn't true any more) I did some analysis on a pretty large number of domains and found that Twitter had virtually no impact on traffic. There were brands that had a large twitter following, but in nearly every case I could find this was because a popular brand happened to have an audience that also was active on Twitter, not because Twitter activity helped to grow their brand.
I also had/have (much more recently) a Twitter account with > 5k follows, that was pretty active (i.e. I didn't just game Twitter to grow followers, something I have done in the past, which is a separate issue). I had a couple of Tweets with more than 1k likes, many with more than 500. First off, most really viral content is viral because it has nothing to do with your "brand", so that gets no traffic. However, even tweets that are relevant, linking to specific articles etc. only get a small blip in traffic and no visible long term improvement.
tl;dr in both my research and anecdotal experience Twitter is not a good marketing tool
Twitter can be good for communicating with your users/audience if they happen to already be there, but it won't grow your brand.
Twitter can be useful for meeting people. I have a small number of friends that I have met there.
But as a marketing tool it is a complete waste of time.