I like that the DDG site search offers options and settings so you aren't stuck with one size, one look. You can customize the appearance. DDG is showing ads but I've never seen more than one or two at the top and they are clearly marked as ads.

Thanks I'll give it a try this weekend but it means another bot that has to crawl my forum with 520K+ messages and it could slow it down.

Runfun, you could consider restricting other bots as a experiment.

Why do you need third party search? Sounds like there's a problem elsewhere and this is a workaround. All forums have native search, and very fast ones too.

The best forum software in the world called BestBBS [webmasterworld.com] has no native forum search. With 520k+ posts I can imagine some slowdown in performance if an internal search option is used.

I meant to write all *modern* forums.
This site is frozen in 1980.

My forum with phpbb did slow down in the past with a previous version. Maybe it's better now but there are more than 520K+ messages at the forum so an internal search function would probably still cause a high page load.

It should be debugged with logs, find the bottleneck.
Is the cpu usage high? Memory? Disk i/o?
I'm sure phpBB can handle 500k posts just fine.
[phpbb.com...]

The server you need depends on the users you have and how you manage it. And also being careful not adding extra plugins (mods) that could hog all server resources like live chats, etc.
There are many things to know to solve this.
Sure add external search but that's a workaround not the proper way to solve an issue.
As for the question i wouldn't do it i would debug the cause of slowness and fix that keeping native search.

/Useless rambling end.

Thanks SweetPotato, thought it couldn't handle it in one of the previous versions. Now it seems working fine and much better experience for users. Only problem is my WordPress part isn't indexed but for this moment it's okay.