List query with, facebook friends in list?
I would suggest the following:

Make 'marked' entities child entities of the users who have marked them.
Use a key name for the 'marked' entity that is based on the URL of the page marked
To find friends who have marked a page, retrieve a list of friends, then generate the list of entity keys from the list of friends (easy, since you know the friend key and the URL), and do a single batch get to retrieve a list of 'mark' entities indicating which friends have marked that page.
In a python based facebook application on GAE, i want to check which friends of current user have "marked" a web page or not.
For this i have to run as many DB queries as the number of friends (say 100)
I fear this may run into "timeout" because of large no of queries.
Google DOCs suggest that "list" queries run in parallel, will this save time ??
Also list has a limit of 30, so i have to make 2 or 3 queries of list type.
Please suggest a better way if possible, using task ques or something....