The Wired October issue has a story about real time search engines and that they are filling a growing trend of real time search demand.

Google will always be around, nobody is questioning that, what they are questioning is that will Google be as effective at delivery real-time search as they are at what they do best, search for static web.

Some of the players mentioned include:
Tweetmeme
OneRiot – Tobias Peggs – Executive – -Google settles arguments – real-time search starts them
Topsy – Rishab Ghosh – “signaling event” burst of tweets on a subject or url
Scoopler
Collecta – Jack Moffitt –  CTO – Collecta real-time search

new techniques including algorithms need to be employed to prevent spamming or tricking the system.