First off, totems only buff people in the same party as the shaman: if you want the warriors and rogues in your raid to get the benefit of Windfury Totem, for instance, they all have to be in the same party as the shaman dropping that totem. This means that poison cleansing, tremor totem, healing stream... these things only affect you if you're in the same group with the shaman.

Furthermore, most totems pulse: they do not have a continuous effect as do various other classes' direct player or party buffs like Blessing of Salvation or Fear Ward. There are some exceptions (I'm reasonably sure that both Grace of Air and Strength of Earth are constant buffs) but, as an example, disease cleansing totem pulses a cleanse every five seconds, it does not simply immunize people by being present.

Furthermore, most totems have a range of about 20 or 30 yards if you get Totemic Mastery. If you are not within range of the totem, it will not provide it's effect. This is why reducing the pulse time on Tremor Totem was a buff, as people were being feared out of its range. It's still possible for that to happen, but it's less likely.

Finally, totems cost mana to drop and trigger the global cooldown. This means that a shaman can't drop them if he doesn't have any mana (the mana costs aren't prohibitive, but no mana equals no totems) and they can't all be dropped at once (you can't macro a four totem drop and expect them all to show up at once, it will take you at least four seconds to drop four totems with the new reduction in their cooldown) and you can't cast a healing spell, for example, and drop a totem at the same time.

This means that sometimes, you will see a totem disappear and the shaman won't immediately drop it again because he's mid-heal or mid-cast. In this regard, enhancement shamans have it easiest, as most of their abilities are instant like Stormstrike or the various shocks.