Getting Random Output Using MySQL

I have a database containing more than 100,000 values. The structure looks something like as follows:

id | countryid | webid | categoryid | title | dateaddedon

If I use basic RAND() considering there are so many ids it won't be able to return a random result. I end up seeing titles of same webid next to each other. I would rather want titles from different webids being displayed. Therefore I figured since there are only 4-5 different values of webid it might be a better option to randomize the output based on this. I am unable to figure out how to define which specific column values should be randomized when using mysql SELECT command.

I am current using following

SELECT * FROM table WHERE countryid='1' ORDER BY dateaddedon DESC, RAND(3)

I am currently using 3 as seed value. I am not sure what kind of impact does seed value have on RAND. I would highly appreciate if someone could explain that too.