The BEST thing to EVER happen for ALT coins is... the Bitcoin reward halving.
1. The Bitcoin reward just got halved, making it unprofitable for most miners using GPUs.
2. Most former BTC GPU miners will be looking for a way to keep mining.
3. Most will find an ALT coin they like and start mining that.
4. This will introduce a lot more volume and users into the ALT coin economy.
5. More stores will start supporting ALT coins because there are more people that use them.
6. I expect one or two alt coins to really take off in 2013 with this extra boost, similar to Bitcoin, with many improvements across the table (miners/protocol/usability/exchange rate).
7. Expect the need for sub-forums in Alternate Cryptocurrency forum soon!
EDIT: Changed the name of thread
If loads of miners jump into mining alt coins won't that make it equally unprofitable, as the difficulty rapidly increases and the price stays the same? The price is unlikely to follow the new difficulty. The number of coins will be the same.
There will be no new volume, just more people desperate to sell their fewer mined coins. Who will buy them? People with bitcoins?
Why would someone sell bitcoins for an alt coin when the inflation rate has just halved compared with the rapidly inflating alt coin?
The current owners of bitcoins own over half of all possible bitcoins - why sell them for a tiny stake in something that almost certainly will fail (most of these alt coins will fail - maybe one can have some success - but the space of possible alt coins is infinite, and each new alt coin muddies the waters even more)