I was perturbed that, when I sent my sim to a community lot, never more than eight other sims turned up, not counting NPCs. In an effort to give my sim more choice of company, I went into config and made a userStartup.cheat. In that, I included the line
uintprop maxNumOfVisitingSims 20

Well, that made no difference to any of the community lots, except for one: the secret society in the university suddenly had twenty members present, and that was much more cheerful. I always used the castle type of secret society lot, and it was too big for only nine sims. Having twenty-one was a vast improvement.

All the other community lots, however, still had only eight visitors. In an effort to improve that, I changed the maxNumOfVisitingSims to 50.

Then my student, Igor, was inducted into a secret society - the first inductee in this university. At first, he went and returned (because it wasn't there), and I installed the castle at the top of the hill. When Igor arrived, it was absolute bedlam. There were fifty members milling around. There is a bridge over the moat at the entrance to the castle, and fourteen sims got stuck on that bridge, with Igor stuck in the middle of them. I got on with adapting the castle as I have done about a dozen times in the past, adding bathrooms and desks, card tables and a pool table; but the fourteen on the bridge would not budge. I made another way over the moat, put a Shiny Time stove in the dining room, and a cook turned up. After the first serving of breakfast, those who had eaten set down their empty plates on overy flat surface, so the cook could not dish up any more. It was just as well that I had maxed my sim's motives before he went there, because it took him six hours to get off that bridge. Then his time was spent clearing up plates, clearing up plates, clearing up plates. Moving was, of course, with glacial slowness. The whole lot was clearly unplayable. Twelve hours after arriving, my sim staggered away, exhausted.

I have now returned the maxNumOfVisitingSims to 20. I don't know whether that will make this secret society playable, or whether it will go on hosting a scrum. I may have loused it up for good. Oh well, live and learn!

Now my question is this: is it possible to make more than eight sims arrive when my sim turns up to the pub, the bookshop, the church, and so on? I'd be grateful for any help.

maxNumOfVisitingSims is introduced as increase number of quests on your home parties and seems like at SS parties also.
It doesn't affect community lots.
Number of visiting sims is calculated mostly from your computer stats (Actually from stats what game thinks your computer has). In example if your videocard is not in database game takes it as lowest. Also game looks at number of activities on community lot, sending more sims onto lots with more activity items.

http://www.leefish.nl/mybb/showthread.php?tid=6901

That was an interesting read. The six lines emphasised in bold type said this in my log:

CPU: 4608.799804Mhz
Chipset: Vendor: 10de, Device: 104a, Board: 809f1462, Chipset: 00a1
Screen mode: 1920x1080x32BPP, 60Hz
Texture memory: 7776 MB
HW T&L: Fixed function: 1 Programmable: 3.0
boolProp enumerateMultisampleLevels true

There was also this:
Name (database): NVIDIA GeForce GT 610 <<NOT FOUND IN DATABASE!>>

Is that why I get only eight visitors in a community lot? Can I do anything about it? Does, for instance, a fishing pond count as an activity item? How about two fishing ponds? Stumbling around in the dark here.

Just another interesting thread to read http://www.leefish.nl/mybb/showthread.php?tid=6882
Also look for info how increase RAM use to 4GB in Sims 2

In another thread someone said that fishing pond doesn't count, You need objects.

In fear and trembling I followed all the steps, but when I came to Save, I was told 'Access Denied'. Must be a state secret. Perhaps I should join MI5?