I think the advice is "don't count on it".... as far as i can remember some rooms have pretty big "fixed" pin boards some dont have any... if you don't bring one and your room aint got one there is a really good stationery/office supplies shop in Broomhill (en route from Ranmoor to Uni) where you can pick one up for a few quid.
As for the theme nights... most people will have something roughly like school uniform for Sunday 18th and then there is a whole week to get ready for beach party. There are about 6 charity shops in Broomhill (see above) which are always good places to raid for fancy dress parties, etc.
What else can i tell you.... when it says "meal times are FROM 5pm...." then pretty much EVERYONE will turn up at 4.55pm meaning HUGE queues (get used to queueing you will do it a lot in intro week!) however dinner is served until 7pm.... if you go at 6.30pm you will pretty much walk straight in.
Oh another top tip.... if you can, get parents to call by a major supermarket on the way to Ranmoor.... stock up on "non-persishable" essentials like baked beans, squash, washing powder, shampoo, etc etc.... there are loads of supermarkets around but you can end up saving a good £50 if you can blag the folks into buying it (mums are especially fond of things like washing powder).
Another thing...some rooms are up 4 flights of stairs...there are "goods lifts" that will fit suitcases (not people though) but these are pretty limited and again there will be a battle to get them when they are free.... keep things in smaller, lighter boxes for ease of movement when you arrive.
Hmmm what else.... you WILL get lost about 10 times on the first day cos the residential corridoors are a bit of a rabbit warren. If you ever get stuck, make sure you have your room number with you... basically all room numbers are in the format NUMBER, LETTER, NUMBER.... the first number is the level that the room is on, the letter is the corridor, and the second number is the room. For example room 5Q13 means you are on level 5, corridor Q, room 13. Therefore if you find yourself outside 6Q13 you need to go down 1 level.
Now then... security.... Sheffield is really good cos it has really little major crime and generally its really student friendly. However there are a few evil people who know it is freshers moving in weekend and there will be lots of people moving in laptops, dvd players, camera's, etc etc. These people are also very good at "blending in" looking like they are students too. Therefore just be carefull not to leave cars/rooms unlocked and unattended. It might be a pain in the behind locking doors everytime you leave the room/car, but do you want to be forking out £800 for a new laptop on your first day?
If you want any general advice about anything Ranmoor, Uni or Sheffield related then there will be about 100 peopleon "intro committee" - people who lived in Ranmoor last year ad who mostly now are 2nd year students.... they will probably be able to answer 90% of your questions, everything from "where are the laundrettes" (good luck in finding them) to "where's the best cheese/rock/RnB night" etc etc. Also all the bar staff are 2nd or 3rd year students who have lived in Ranmoor so if all else fails head to the bar and collar one of them
On the subject of the bar, again be prepared to queue as it will be very busy, although its a good way to meet people while you are waiting. It speeds things up if you order ROUNDS for people rather than everyone buying drinks individually. The bar is a really good for lots of things... big screen for footie, rugby, etc.... pool tables.... beer garden.... drinks are cheap (Carling £1.60, Double Vodka £2, Coke £1/pint) and there are usually plenty of offers on too.
Oh one final bit of advice.... if you want to avoid having the same conversation with 200 people then get a t-shirt printed with your name, where you come from, your A-level results and what course you're doing (trust me this is THE main opening to every conversation for at least the first 4 days)