Hi venkat_O2,
1. message-uid and highlight/true are both used to higlight certain messages in the thread. They're typically used in conjunction with an anchor tag to "jump" to the desired message. For example:
http://lithosphere.lithium.com/t5/Lithium-Developers/More-on-Colors-Customizing-the-Mobile-Interface/m-p/29972/message-uid/29996#U29996 - In this case, 29972 is the message uid of the thread, and 29996 is the message uid of my reply.
http://lithosphere.lithium.com/t5/Lithium-Developers/More-on-Colors-Customizing-the-Mobile-Interface/m-p/29996/highlight/true#M276
2. For communities that have enabled our Mobile view, the device-view query parameter allows you to specify whether you want to see the page optimized for desktop devices or optimized for mobile devices. For example:
http://lithosphere.lithium.com/t5/Lithium-Developers/More-on-Colors-Customizing-the-Mobile-Interface/m-p/29972?device-view=desktop
http://lithosphere.lithium.com/t5/Lithium-Developers/More-on-Colors-Customizing-the-Mobile-Interface/m-p/29972?device-view=mobile (WARNING: If you click this link, you will need to click the "Full" link at the bottom of the page to get back to Desktop view, or manually append ?device-view=desktop to the URL)
Regarding crawling in general, I'd definitely suggest you check out our Crawl List feature, which may suit your needs better than trying to crawl through the entire community. Here's more information about it:
http://lithosphere.lithium.com/t5/Customer-Connection-Private/Crawl-List/ta-p/19246
http://lithosphere.lithium.com/t5/Customer-Connection-Private/Implementing-federated-search-using-a-crawl-list/ta-p/7275