As most of connection you will get on Facebook relate to real connections from your email Adresbook .Here some help to use your gmail search rutines to find some conversation or contacts you stored on a gmail account . As when you setup your gmail account with a Imap you will find many old contacts too reconect with facebook

It builds a strong search tool, but how you find your specific mail in tausends of archived emails over the last years .

The Bolean search terms for the Gmail box

Use the following search  operators:

STANDARD SEARCH

• subject: – Search the Subject line.
  Example: “subject:bahamas” finds all messages with “bahamas” in the Subject.
• from: – Search for sender name and email address. Partial addresses are okay.
  Example: “from:heinz” finds all messages from “heinz@about.com”, but also all messages from “your.heinz@newsmedia.at”.
• to: – Search the To line for names and addresses.
  Example: “to:querytome@gmail.com” finds all messages sent directly (not via Cc: or Bcc:) to querytome@gmail.com.
• cc: – Search recipients in the Cc field.
  Example: “cc:quertyuiop@gmail.com” finds all messages that were sent to querytome@gmail.com. as a carbon copy.
• bcc: – Search for addresses and names in the Bcc field. Note this only works with emails you sent to Bcc recipients from Gmail.
  Example: “bcc:heinz” finds all messages that you sent with, for example, “hein@example.com” in the Bcc field.

LABEL MAIL SEARCH

• label: – Search for messages assigned a label. (Replace whitespace characters in label names with hyphens.)
  Example: “label:toodoo-doll” finds all messages labeled “toodoo doll”.
• is:starred – Search for messages that are starred.
• With Superstars enabled: Superstar is available in the google lab
  • has:yellow-star – Search for messages with a yellow star.
  • has:red-star – Search for messages with a red star.
  • has:orange-star – Search for messages with an orange star.
  • has:green-star – Search for messages with a green star.
  • has:blue-star – Search for messages with a blue star.
  • has:purple-star – Search for messages with a purple star.
  • has:yellow-bang – Search for messages with a yellow exclamation mark.
  • has:red-bang – Search for messages with a red exclamation mark.
  • has:purple-question – Search for messages with a purple question mark.
  • has:orange-guillemet – Search for messages with two orange forward arrows.
  • has:blue-info – Search for messages with a blue i.
• is:unread – Search for new and unread messages.
• is:read – Search for messages that have already been opened.
• 
  

SEARCH BY MAIL CONTENT

• has:attachment – Search for messages that have files attached to them.
• filename: – Search within file names of attachments. You can also search for file name extensions to restrict your search to certain file types.
  Example: “filename:.doc” finds all messages with word processing attachments.
• is:buzz – Search for Google Buzz posts.
• is:chat – Search for chats.
• lang: – Search for messages in a particular language. (Specify the language in English; “Chinese” works, but “中文”, “Putonghua” or “Mandarin” do not, for example.)
  Example: “lang:French” returns all emails that contain at least un peu de Français.
• in: – Search in a standard “folder”. You can search in Drafts, Inbox, Chats, Sent, Spam, Trashand anywhere (for everything, including Spam and Trash).
  Example: “in:drafts” finds all messages in your Drafts folder.

TIME DATE Search in GMail

• after: – Search for messages sent after a date. The date must given in YYYY/MM/DD format.
  Example: “after:2012/04/04” finds all messages sent or received after (and not including) April 4, 2012.
• before: – Search for messages sent before a date.
  Example: “before:2012/04/04” finds all messages sent or received on April 4, 2012 and earlier.

Operators and search Combinations  with  modifiers:

• By default, terms are combined with (an invisible) “AND”.
  Example: “shepherd macaroni” finds all messages that contain both “shepherd” and “macaroni”.
• “” – Search for a phrase. Case is disregarded.
  Examples: “shepherd’s macaroni” finds all messages containing the phrase “shepherd’s macaroni”; ‘subject:”shepherd’s macaroni’ finds all messages that have “shepherd’s macaroni” in the Subject field.
• OR – Search for messages containing at least one of two terms or expressions.
  Examples: “shepherd or macaroni” finds messages that contain either “shepherd” or “macaroni” or both; “from:heinz or label:toodoo-doll” finds messages that either come from a sender that contains “email.guide” or appear under the label “toodoo doll”.
• – – Search for messages that do not contain a term or expression.
  Examples: “-macaroni” finds all messages that do not contain the word “macaroni”; “shepherd -macaroni” finds all messages that contain the word “shepherd” but not “macaroni”; ‘subject:”shepherd’s macaroni” -from:heinz’ finds all messages with “shepherd’s macaroni” in the subject that were not sent from an email address or name containing “heinz”.
• () – Group search terms or expressions.
  Examples: “subject:(shepherd macaroni)” finds messages that have both “shepherd” and “macaroni” somewhere in the Subject line (but not necessarily as a phrase); “from:heinz (subject:(shepherd OR macaroni) OR label:toodoo-doll)” finds all messages from a sender who has “email.guide” in their name that either have “shepherd” or “macaroni” (or both) in theSubject line or appear under the label “toodoo doll”.

Nice overview on a PDF by CCCC.edu