I’m a great fan of Buffer, a simple and free tool that lets you schedule tweets and Facebook updates (both for profiles and pages) in advance – but which automatically times them for slots when they are likely to get the most response.
That is really handy when you want a message to be seen or acted on, but it isn’t too time sensitive. You can manually schedule messages with many other tools, but Buffer takes the extra step of letting you set up a series of prime time slots and then it automatically puts each message you schedule into the next one of those slots which is free. You can also use it with LinkedIn and some other social networks.
Very nifty, especially as it means that – for example – you can trawl through handy Twitter lists for various messages to retweet and then use Buffer to spread out your retweets over an effective time range rather than have them all appear in one concentrated deluge.
I’ve found the service very reliable – occasional interruptions when lining up a message, but never failing to send one and never making a mess of sending one more than once. They have also been very responsive to questions I have sent their way. Most recommended.