What is the use of

 blcontinue - When more results are available, use this to continue.

I have not be able to get how to use this feature and what values it can take as documentation does not mention about it.

Also what does this part of the result signify

<query-continue>
  <backlinks blcontinue="0|Delhi|460979" />
  </query-continue>
when i ran the following query 

http://en.wikipedia.org/w/api.php?action=query&list=backlinks&bltitle=Delhi&bllimit=500&blfilterredir=nonredirects&blnamespace=0


--
Ankuj