Really not much you can do with the list. But I would do the following to make it look a little better:
a) Use two columns, one for the user name, the other for the boolean visit. Make column 1 be a fixed width either in percent or in pixel size. Make column 2 the remainder.
Name Visit
User1 1
User2 0
User3 0
User4 1
b) Sort the list out alphabetically
c) Change the font to verdana or some sans-serif font
d) Alternate the colors for each row. Say white for all even numbers and a light cray #cccccc for the odd colors.
e) Use a background color for the column headings
Use CSS to pull this off.