A lot of people manage on very little land, such as a garden, and goats will readily adapt. Must be well fenced though!! If its a small space, then there is extra work bringing in green feed, in the form of grass, branches etc, and they need a constant supply of hay too.
At my old house, I had about one third of an acre, and had 6 goats living there. They came in every night, and had access to hay all the time, and I gave them plenty of leaves from the trees. Kept them in over winter to allow the grass to grow again, and it worked well for me. So, a small paddock that size, would keep two goats easily.
Also the size of the plot depends on the size of the goat. For example, pygmy goats need a lot less space, that the large rangey dairy breeds, who like to have space.