17. At least one computer-readable medium having computer executable instructions, which when executed perform steps, comprising: receiving a URL visit log and an input set of users, the URL visit log indicating URLs visited by the users in the input set of users, each URL in the visit log having a domain; building a table of cells comprised of the domains of the visit log crossed with the set of users; for each cell, computing a count of visits to the domain corresponding to the cell by the user corresponding to the cell, where the count in a cell comprises a count of the URLs in the visit log that belong to the domain corresponding to the cell and that were visited by the user corresponding to the cell; and suggesting domains by using the counts of the cells to compute similarity between pairs of domains and using the similarities to suggest domains in the table.
17. At least one computer-readable medium having computer executable instructions, which when executed perform steps, comprising: receiving a URL visit log and an input set of users, the URL visit log indicating URLs visited by the users in the input set of users, each URL in the visit log having a domain; building a table of cells comprised of the domains of the visit log crossed with the set of users; for each cell, computing a count of visits to the domain corresponding to the cell by the user corresponding to the cell, where the count in a cell comprises a count of the URLs in the visit log that belong to the domain corresponding to the cell and that were visited by the user corresponding to the cell; and suggesting domains by using the counts of the cells to compute similarity between pairs of domains and using the similarities to suggest domains in the table. 18. The computer-readable medium of claim 17 wherein computing the similarity between the pairs of domains comprises selecting two domains in the table and using a Pearson coefficient function to compute the similarity between those selected domains.