While doing some shopping online I came across the following clause in the terms of service from an online store. I would tell you where I got it from but after reading it you’ll know why
7. NO LINKING, FRAMING, MIRRORING, SCRAPING, DATA-MINING OR POSTINGS
Links to the Website without the express written permission of 1GCB are strictly prohibited. To request permission to link to the Website, please send an email to firstname.lastname@example.org. 1GCB may in its discretion cancel and revoke any permission it may give to link to the Website at any time and without any notice or liability.
The framing, mirroring, scraping or data-mining of the Website or any of its content in any form and by any means is strictly prohibited. You may not use any collaborative browsing or display technologies in connection with your use of the Website or to post comments, communications, or any other data of any kind to or on the Website with the intention that such postings may be viewed by other users of the Website.
Brownie points for a clause against data-mining and scraping, though.