Dharmatel - Most likely the Dharma Intiative's intranet (that is also referred to on the map). The network that links the station's computers, allowing for communication. However, the omitted part of The Swan's Orientation film states that the computer (at least in The Swan) is not to be used for any purpose other than the input of the code, and warns that if it is used for communication then it may result in another "Incident".

Kelvin Inman described the 'Incident' as a leak in the "geologically unique source of electro-magnetism" that The Swan housed, but does not specify what actually caused this leak. Perhaps it was linked to an power overload due to continuous communication between the stations. This could fit, since the Dharmatel/intranet was apparently shut down, according to the map - (These notes could mean that, due to the Incident, the Dharmatel Intranet was shut down.

On the map, there are faint light-blue lines that link all of the stations together. However, whilst the ring of standard stations connect to two stations each, The Pearl appears to be connected to all of them (with the exception of C4, which I think is The Hydra. Why The Pearl does not have a link to C4 on the map is unknown). This could mean that the Dharmatel was perhaps used to transmit live video feed, or to allow communication through the computers.


Smaller structures - "CV I", "CV II", "CV III", and "CV IV"

• Quote:

  CV I - HIGHLY UNLIKELY

• Quote:

  POSSIBLE CV II - INACTIVE SINCE ACCIDENT.

• Quote:

  CV III

• Quote:

  CV IV?

What these smaller structures actually are has not been explained or even hinted at. There are a few notes that could apply to 1 of them, but it does not give any details as to what they are.

The way CV II is described as being "INACTIVE SINCE ACCIDENT" could be inferred as saying that 'CV structures' are perhaps power substations or network relays (for the "Dharmatel").


Scribbled out station - "C1"

• This station is mainly believed to be the false station that The Others had in their decoy camp. When Sayid discovered this camp and open the doors to their "hatch", he found nothing but a space not much larger than that of a walk-in cupboard.
  
  It is possible that it was once a hatch that had caved in (hence why it was blocked up). Evidence to support that it was once an actual station can be seen on the map -
  Quote:

  ALLEGED LOCATION OF ABORTED #7 LARGE NUMBER OF UNDERGROUND SPRINGS HEAVY WATER TABLE

  - which implies that there was a 7th station. However, this quote may simply apply to The Flame, since the note is located close to The Flame (one could presume that The Flame is Station '7').
  
  But this seems unlikely, since the Orientation films describe The Swan as "Station 3 of 6" and The Pearl as "Station 5 of 6", which means that 'station 7' was likely aborted prior to the start of the Dharma projects.

There are also numerous equations dotted around the map. It turns out that most of these equations are related to electro-magentism.


So there you have it. The Blast Door Map has many more notes, but right now they do not seem to have much meaning.