
I spend a ton of time digging around for specific posts I've read before, or have written myself. I know to use the search function, but often it would return either zero results or a gazillion - neither of which is very useful.
Until we switch to another search system or forum software, the current Vbulletin search function will still be our best friend. And I think it's time to get to know this friend better!
Limitations
First of all - here are some limitations of the search function:
Examples of common words are who, what, which, where, why.
Basic Search Syntax
You can search multiple words using Boolean operators such as:
(Reference: Vbulletin Forum)
Examples and Notes
1)Do NOT mix a phrase in quotes with booleans - or else the posts returned may not contain the phrase (it will sometimes, if you're lucky):
"historical data" AND whitelist <--- will NOT work; you won't even find the word "historical" in some of the search results, let alone the phrase "historical data"
2)Do NOT tag extra words onto a phrase in quotes - again, search results may not contain the phrase in quotes (it will sometimes, if you're lucky):
"lander CTR" stats <--- will NOT work; you won't find the phrase "lander CTR" in the search results
3)Keywords with only 3 letters will normally get excluded. However, if you need to include 3-letter search terms, DO try putting it inside a phrase - sometimes that will work.
"pop traffic" <--- WILL work
pop traffic <--- will NOT work; only the word "traffic" will be searched for
4)Note that even in a phrase in quotes, common words will be excluded. e.g.:
"cost and revenue" <--- the "and" will be excluded from the search
Advanced Search Options

When you click on the "Advanced Search" link under the search bar, you'll see more search options.

These options should be self-explanatory. Basically just provide as many pieces of information as you know to narrow down the search results.
If on the other hand you're getting ZERO results returned, then try to do a broader search by removing some of the restrictions, or specify fewer keywords, or both.
If anyone has extra tips on how to use the search function more effectively, please share them below! 
Amy
Great post!
My top tips on forum searching:
1) Restrict the search to the title of the thread if you're looking for a tutorial. (That's under the "search entire posts" dropdown.) That makes it far easier to find the thing you're looking for most of the time.
2) Restrict to specific named authors (under "User Name"), and further to "Threads Started By User". If there's a tutorial on the forum, for example, chances are it was written by one of the mods or admins - so search on their names and you should find what you're looking for.