The highlights for SmugMug (not Google) searching

• Searching for part of a word will not return the full word.  E.g. searching for sweet will not return photos labeled as sweetheart. Tiger will not return a photo labeled as tigers.
• SmugMug indexes up to 30 keywords per photo.
• Searching for two or more words will return only photos or galleries that contain each of those words.  Order does not matter. E.g. searching for Ball Sweetheart will return results for galleries/photos that contain the word ball and the word sweetheart. 
• Case does not matter. So Ball and ball will return the same results. 
• Searching for two or more words enclosed in quotation marks will return all photos or galleries containing ANY of the words.  E.g. searching for "sweetheart ball" will return all sweetheart results and all ball results.
• There is a three letter minimum on searches. We'll just silently disregard a two letter word (or common words like the, for, or and) if you use it in a search such as to the ball.
• Numbers searches will return gallery or photo results if that number is a part of a caption, gallery title, gallery description, or if it comprises a keyword.  However, no keyword containing a number will be returned as a keyword search result.  They are browsable through your keyword cloud: http://yournickname.smugmug.com/keywords , however,  and will be listed under the photo and clickable.
• The gallery keywords box in your customize gallery settings for a gallery will be indexed as long as that gallery also has a description (and is public, not protected by a password, and has Hello Smuggers set to yes).
• When you're logged in, your entire SmugMug site will be searchable, regardless of your security or privacy settings. Hidden photos are searchable as well.
• Logged-out visitors will never see hidden photos in search results and they will never see unlisted galleries or the photos they contain in search results. 
• Assuming your Hello Smuggers SmugIslands settings allow visitor searching, visitors will find galleries and photos for public, non-password protected galleries.  After they have entered a gallery password, they can search for photos within a password-protected gallery. However the gallery itself will not come up in search results.

Examples

To illustrate how SmugMug searches work, I created some sample galleries and captioned and/or keyworded photos as followed:

Gallery 1

Title: Sweetheart Ball
Description: None

Gallery 2

Title: Sweethearts Ball
Description: None

Gallery 3

Title: Testing
Description: Sweetheart Ball

Gallery search results:

I typed the following in the search box and received the indicated results:

Search: Sweetheart
Search: Sweetheart Ball
Search: Ball Sweetheart
Gallery Result for each: Galleries 1&3

Search: Ball
Search: "Sweetheart Ball"
Gallery Result for each: Galleries 1, 2 &3

Search: Sweet
Search: heart
Search: test
Gallery Result for each: No galleries found.

The photo search results are independent of the title or description of the gallery in which they are contained.  Therefore, I simply keyworded or captioned each photo and documented the search results below.

Photo 1

Keyword: "Sweethearts ball"

Photo 2

Keywords: "Sweetheart ball"

Photo 3

Keywords: Sweethearts, ball

Photo 4

Keywords: Sweetheart, ball

Photo 5

Keywords: Sweet, heart, ball

Photo 6

Caption: Sweethearts ball

Photo 7

Caption: Sweetheart ball

Photo 8

Caption: Sweet heart ball

Photo and Keyword search results:

I typed the following in the search box and received the indicated results:

Search: Sweethearts
Photos Result:  3, 6
Keywords Found:  "Sweethearts"

Search: Sweet
Search: heart
Photos Result for each:  5, 8
Keywords Found: "sweet" or "heart"

Search: Ball
Photos Result:  1-8 (all of them)
Keywords Found:  "ball"

Search: sweetheart
Photos Result:  2, 4, 7
Keywords Found:  "sweetheart"

Search: sweetheart ball
Photos Result:  2, 4, 7
Keywords Found:  "sweetheart", "ball"

Search: "sweetheart Ball"
Photos Result:  1-8 (all of them)
Keywords Found:  None