like it! good idea!

I think what you want to do is tag those waiting tasks and then you can exclude them from various searches or focus just on them as you wish. Smartlists can often be the tool that lets you obtain the features you want from RTM today, without having to wait for Bob to code any changes at all.

I agree with ranbarton. Tag them with "wait", exclude them from your primary list (the one where you look at what you have to do every day), then create a list that searches for tag:wait. Thus you avoid keeping it "in your head" but you avoid forgetting.
For this method to work you should ignore the overdue status of the task.

+1 agree with ranbarton ^^

Either tag them wait, or put them on a seperate list "waiting for" which you can look at weekly or whichever.

This feature would be best combined with the addition of a Start Date and Task Dependencies (these are two other suggestions already offered and are receiving a high number of votes).

Agreed, tag + start_date would be the way to go.

Great idea, f.ex when i'm waiting for customer confirmation of activity from the task.

I primarily use priorities instead of dates.
I select at the beginning of every day things that I should focus on for the day, assigning priority 1.

To visualize things, I group items by priority indeed.

All the items in waiting state (= have a #waiting tag to mark that I'm waiting e.g. for an email reply from someone) also have priority 1.

My problem is that items with priority 1 with things to do for the day and things in waiting state got mixed in the visualisation. It is not possible e.g. to sort them so that items in waiting state appear all together before or after

@luca.minudel What you can do is sort by tag. In that case, tasks with the #waiting tag comes before/after tasks without that tag, depending on whether you're sorting by tag ascending or descending. You can also group by tag. In that case, the tags are separated in the list view.

To do custom sorting and grouping, press on the cog wheel above a list and select Advanced sorting.

I use tags for waiting or put @awaiting at the front of the task name which is then easy to search on

In general the easiest way to work is to design your own taxonomy of meaning(s) and express those with tags. Then use smart lists to grab just those tasks that are the right set (has tag A AND tag B AND (NOT Tag C) OR Tag D -- etc). Use the dynamic stuff (related to times and dates, priority and other status that changes during the lifetime of a task) to group, order and otherwise shape your lists.

In my setup, tasks that are waiting for something get a #w4 tag, which is used for exclusion from pretty much all operational smart lists. Use the tag itself to gather al your 'waiting fors' in one place.